Distrust of Muslims has become a toxic refrain in the West, characteristic of Donald Trump’s successful campaign for presidency and of far-right political groups across Europe. One poignant photo by a young Danish photographer captures just how isolating that can feel.

At a public meeting in March about proposals to create a refugee center in Kalundborg, Denmark (about 70 miles west of Copenhagen), photographer Olafur Gestsson observed rows of residents voicing their opinions. Some came to...